Soil compacting machine

ABSTRACT

A soil compacting machine has a frame carrying two soil compacting rollers mounted in tandem and at least two out of balance centrifugal force generators for vibrating the rollers as they roll the soil. At least one of the generators is mounted on the frame in front of the rollers and at least one other generator is mounted on the frame behind the rollers and both these generators are carried on shafts which extend longitudinally in the direction of travel of the machine and are relatively short compared with the width of the frame and the axial length of the rollers.

United States Patent s www www ggco0 gguen eeenea annOnmmm aa. a MKKMKM512389 566666 999999 llllll l//l/ 2900324 l l 789841 778674 2,2.0.6.l7.808255 2048113 7.0.0.0,4,4, 233333 n a m m a. .l .D wm n w m ma .M 9 mm%W.M 3 v .mm77r .h 1.2M. u w3, sh. ohSuu l. SAI. f de .0. N mc n rd n m.e Pee... v Pm .m AFPA l. lill. 2 |253 7 2247 l l.l||i

mbH., (BOMAG), am Gueterbahnhof Boppard/Rhein, Germany PrimaryExaminer-Nile C. Byers, Jr, Attorney-Arthur O. Klein m l Hmm i n D. .uAAw .H .m .l P lll 23|.. 333 lll [54] SOIL COMPACTING MACHINE ABSTRACT: Asoil compacting machine has a frame carrying l2 Claims, 6 Drawing Figs.

two sol compacting rollers mounted in tandem and at least two out ofbalance centrifugal force generators for vibrating 94/50 --E01 19/ 28the rollers as they roll the soil. At least one of the generators is94/50, 50 mounted on the frame in front of the rollers and at least oneV48 other generator is mounted on the frame behind the rollers and boththese generators are carried on shafts which extend longitudinally inthe direction of travel of the machine and are [5l] lnt. [50] Field of[56] Reierences Cited UNITED STATES PATENTS 4/1949Pollitz...............

relatively short compared with the width of the frame and the axiallength of the rollers.

PATENTE!) JuLz vany snm 1 or e 3.595.145

/NVE/v roR: Ummm Mozo'zANowsm www@ ATTQRNEy PATENTEU .lum Isn .3, 595,145

` SHEU a nf e /fv vE/v rom Beocbim M OZDVZANOWSKl ATTO R N Ey PAN-:mmmmn595,145

WMU@

ATTORN Ey PATENTE!) Jule? |971 SHEET u F 6 /NVEN TOR: 'JoachimMOZDZANOWSKI ATToRNEy PATENTED JuL2 7 lan SHEET S UF 6 N m @E AVVE/WOR.-

Bgwm MoznzANowsm v 'mw 0. @M

ATToRNEy PATENEU .m2715171 3,595,145

oachcm MozozANowsm ATTORNEY SOIL COMPACTING MACHINE can take theform ofa towed roller and there may be only one generator.

The unbalancedcentrifugalforce generators are mounted on shafts and itis the usual practice to arrange these shaftsso Athat they extend'acrossthe frame of the vehicle, that is'to say perpendicular to the directionof travel. Each generator is usually as long'asrthe-rollers ofthemachine, that isto-say the generator extends rightacross thewidth vofthe machine. This makesit necessary to use long shafts for thegenerators, with the result that the shafts flex considerably. Thediameters of the generator shafts are limited by the. amountof spaceavaila ble. Moreover the generator shaftsare usually drivenfrom onesidefof the vehicle, and thiscauses difficulties. It is desirable tokeep at least one side of the machine free from driving mechanisms, sothat the machine can be driven as close as possible to edges andvertical surfaces. For thisreason existing soil compacting machineshavethe drives for propelling the vehicle and for rotating the wobblegenerators on one side only of the vehicle. Thisv arrangement howevergives the machine an awkward shape, and results in a one-sideddistribution of the masses, which makesit necessary to provide balancingweights.

A vibratory compactor for yroad surfaces is known inwhich two shafts aremounted on the machine frame,abovethe rollers. These shafts extend' inthe direction of travel and are driven in opposite senses. 0n the shasare mounted un-y balanced centrifugal force generators which can beshifted in position along the shafts, so as to vary the oscillationamplitude. A single `roller compactor is disclosed in U.S. Pat.No.3,176,597 in which a vibrator is mounted over the roller and this.vibrator has `generators whose shafts extend in the direction of travelof the machine. However this machineis entirely different in kind fromthe machine with which the present invention is concerned because itgives. only a vertical translatory movementwhereas a double vibratoryrollerl provides a rotary oscillation.

All the known unbalanced centrifugal force generators arranged in theform of double vibratory rollers have this disadvantage in common, thatthey have long generator shafts, which usually extend all the way acrossthe machine and are therefore subjected to considerable bendingstresses. The lresulting flexion of the shafts applies undesiredstresses to the drive. It is difficult to prevent the flexion withoutwasting considerable space, and the attempts to prevent the flexion ofthe shafts sometimes fail due to the lack of available space.Furthermore if the generator shafts are of large diameter, the

bearings also have to be correspondingly large. This is not onlyA costlybut also involves a high rate of production of heat, because of course alarge bearing produces heat more rapidly than a small one.

Thel object of the ypresent invention is to `arrange the unbalancedcentrifugal force generators of a soil compacting machine in such a waythat thecost of construction is reduced and in such a way that itbecomes possible to position the generators at the bestlocations in themachine for producing the desired rotary oscillation, that is to say`for giving the machine the desired rocking movement. l

To this end according to this invention, the generators in a l soilcompacting machine comprising at least two rollers arranged in tandemand mounted in a frame, and at last one out of balance centrifugal forcegenerator is mounted `in the frame.- lf therel areA two out .of balancecentrifugal forced generators provided, one is mounted in front of andone behind the rollers on short shafts extending in the directionoftravel of the machine.

The-shafts of the generators are much shorter than the rollers or muchshorter than the width of the frame of the machine. The generators maybe mounted in housings in the form of transverse members which rigidlytie together longitudinal side members of the frame. Each transversebeam may contain several generators, the drives of which need not belocated in or on side members of the frame.

Using very short generator shafts provides the important advantage thatthey can have comparatively small diameters, and the bearings can becomparatively small. ln a preferred example of the invention the shaftsof the generators are located at substantially the same'height as axlesonvwhich the rollers are mounted. With this arrangement particularadvantages can be obtained by mounting in each end of the machine, two,four, or even more generators rotating in opposite directions, to theeffect that a directional oscillation is obtained. This has theadvantage that the system of generators produces no forces which stressthe frame of the machine in tension. The same advantage may of course beobtained by mounting one generator at each end of the machine, but thiswould result in oscillations about the middle vertical axis of the.vehicle. Generators rotating in opposite directions are thereforepreferred.

Arranging the shafts of the generators so that they extendlongitudinally in the machine, that is to say in the direction oftravel,.allows the drives to be accommodated between vertical planescontaining the longitudinal side members of the frame, and above therollers. With this arrangement it is not necessa- Vry to position thepropulsion drive for the machine, and the drive for the generators atone side of the machine. The

machine is therefore comparatively narrow, and the soil can i becompacted close up to vertical surfaces. The generators may be drivenand if necessary synchronized by means of gear wheels. Each generatormay for example take the form of a toothed disc the teeth of Awhichengage with those of a neighboring disc.

ln a preferred example of the invention, the drive for the generators isby means of a toothed belt which has teeth on both sides. The beltextends around a driving disc, around four toothed generator discs andaround an idler roller, in such a way that pairs of generator discsrotate in opposite directions. The same principle can be applied to morethan four generator discs. lf desired the generators can be driventhrough Carden shafts.

The engine, which drives the generators and also serves for propulsionof the machine is preferably spring mounted on the frame of the machinesubstantially centrally. The drive may be mechanical, or if desiredhydraulic.

An example together with some modifications of a soil compacting machineconstructed in accordance with the invention is illustrated somewhatdiagrammatically in the accompanying drawings in which:

FIG. l is a side view of the machine;

FlG. 2 is a plan view;

FIGS. 3 to 6 are end views of the machine and of the machine modified bythe substitution of different centrifugal force generators.

The machine has four rollers l, 3 and 2, 4, rotatably mounted on axles 5and 6, the ends of which are fixed in side members 7, 8 of a frame ofthe machine. Gear wheels 25 for driving the rollers l, 2, 3, 4 aremounted on axles which rotate in bearings in the members 7, 8. A sourceof power, in this example a Diesel engine 13 is spring mounted above therollers on a supporting frame 1S, there being disposed coiled springs14, or other springing devices, between the supporting frame 15 and theframe of the machine. The driving engine 13 drives a hydraulic pump 16on a flange of which a controller 17 is mounted. The driving engine 13,the hydraulic pump land the controller 17 form a single structural unit.

For the propulsion drive, the engine 13 drives hydraulic pumps 50 and51, the hydraulic fluid passing through pipes 54 and S to drivehydraulic motors 52 and 53.

From the hydraulic pump 16, pipes 18 convey hydraulic fluid to hydraulicmotors 19 and 20, one at each end of the frame. The two hydraulic motors19 and 20 dn've gear wheels 29, 30 which rotate in bearings in twotransverse frame members 9 and l0, at the front and rear ends of themachine. The two transverse members 9 and 10 form housings whichcontain, as shown for example in FlG. 3, unbalanced centrifugal forcegenerators 31, 33, 35, 37 and 32, 34, 36, 38 in the form of unbalanceddiscs on short shafts 1l, 12 extending longitudinally in the machine,that is to say in the direction of travel. Each disc has peripheralteeth engaging with those of a neighboring disc. The drive from the gearwheels 29 and 30 mounted on the shafis of the hydraulic motors 19, 20 istransmitted from toothed wheels 39, 40 to the generator discs 33, 34 bytoothed belts 56. lf desired, instead of what is shown in the drawings,the machine can be equipped with a single generator disc, to give acircular oscillation. Preferably however the generator discs arearranged in oppositely rotating pairs to give a directional oscillation.

For synchronizing the generators at the front and rear ends of themachine there are connecting shafts 22, 23 with flexible joints,connected together by a middle shaft 24.

In the modifications shown in FIGS. 4 to 6, the generators are drivenand synchronized by a toothed belt 4l, which has teeth on both sides. lnthis case the generators 42 to 45 do not engage directly with eachother. Each generator disc has peripheral teeth which engage with theteeth of the belt 41. The belt 4l is trained around the discs in such away that the discs 42 and 43, and the discs 44 and 45 (not shown) aredriven as oppositcly rotating pairs, ln FIG. 4 for example, the belt istaken anticlockwise around the disc 42, and clockwise around the disc43. When the two unbalanced weights, in dicated by broken lines in thedrawing, rotate in opposite directions, they simultaneously reach theirextreme upper, lower, inner and outer positions, producing a directionaloscillation.

Similarly the toothed belt 4l is taken clockwise around the disc 44 andanticlockwise around the disc 45. The drawing shows a toothed wheel onthe shaft of the hydraulic motor at 30a, and an idler roller at 46.

If the machine in accordance with the invention is in the form of adouble vibration roller, that is to say a doubleroller rocking-actioncompactor, arranging the generators in the manner in accordance with thepresent invention has the particularly advantage that the longitudinalchasses members do not have to take the longitudinal stresses applied bygenerators which are positioned at the two ends of the machine and are180 out of phase, in passing through their extreme outer and extremeinner angular positions. A special advantage obtained by mounting thegenerators with their axes extending fore-and-aft, is that the generatoraxles can be mounted to rotate in bearings in the cross members of thevehicle, or in housings arranged transversely in the vehicle, so thatthe system of generators can easily be removed from the vehicle formaintenance purposes. This advantage is obtained irrespective of whetherthe generator discs drive each other directly by their teeth, or aredriven individually by a toothed belt.

Mounting the generator discs on short shafts extending longitudinally inthe vehicle also provides the particular advantage that the generatorscan if desired rotate at different speeds, or rotate withoutsynchronization. For example the forward generator can give anoscillation frequency of 30 Hz., the rear gehemmt giving an oscillationat 47 Hz. A vertical rocking motion results with a frequency of l7 Hz.which is approximately the resonant frequency of the soil. By varyingthe frequencies the vertical rocking movement can be made to agree withthe resonant frequency of the particular soil, giving a particularlyfavorable compacting effect. ln this way the machine can be adjusted foreach particular type of soil.

The particular advantages of the machine in accordance with theinvention are, in the first place, that any desired pairs of generatorscan be selectively installed at the front and rear ends of the machine.The generators can be driven to rotate at any desired speeds, forexample by using gear wheels of different diameters, to suit differentoperating conditions. Locat ing the power source in the middle of thevehicle minimizes the width of the vehicle. Locating the generators nearthe ends of the machine provides the greatest possible vibratory rockingtorque.

Although the invention is illustrated and described with reference to aplurality of preferred embodiments thereof, it is to be expresslyunderstood that it is in no way limited to the disclosure of such aplurality of preferred embodiments, but is capable of numerousmodifications within the scope of the appended claims.

lclaim:

1. ln a soil compacting machine including a frame, at least two soilcompacting rollers, means mounting said rollers in tandem in said frame,at least two out of balance centrifugal force generators and meansmounting said generators in said frame, the improvement wherein saidgenerator mounting means includes first means mounting at least one ofsaid generators in front of said rollers and second means mounting atleast one other of said generators behind said rollers both said firstmeans and said second means including a relatively short shaft extendingin the direction of travel of said machine.

2. A machine as claimed in claim l, wherein said means mounting saidrollers in said frame includes horizontal axle means and furthercomprising bearing means mounting said shafts of said first and saidsecond means at substantially the same height as said axle means.

3. A machine as claimed in claim l, wherein said frame includeslongitudinal side members and transverse members interconnecting saidlongitudinal side members in front of and behind said rollers, saidtransverse members including portions defining housings and saidgenerator mounting means mounting said generators in said housings.

4. A machine as claimed in claim l, wherein said frame includeslongitudinal side members disposed one at each end of said rollers andfurther comprising engine means and drive means operatively connectingsaid generators to said engine, said drive means being located abovesaid rollers and between vertical planes containing said longitudinalside members.

5. A machine as claimed in claim l, wherein each of said generatorsincludes a pair of unbalanced discs, means rotatably mounting said discsand means for rotating said discs in opposite directions to each other.

6. A machine as claimed in claim 5, further comprising peripheral teethon said discs, said teeth of said discs in each of said pairs of discsmeshing with each other.

7. A machine as claimed in claim S, further comprising peripheral teethon said discs and toothed belt means meshing with said teeth on saiddiscs of each of said pairs.

8. A machine as claimed in claim 7, further comprising teeth on bothsides of said belt, an idler roller, and means extending said beltaround said idler roller, around one of said discs in said pair in aclockwise direction and around the other of said discs in said pair inan anticlockwise direction.

9. A machine as claimed in claim 1, further comprising means for drivingsaid generators, means mounting said driving means on said frame anduniversally jointed shaft means operatively connecting said drivingmeans to said generators.

10. A machine as claimed in claim including engine means for drivingsaid generators, means mounting said engine means on said frame,ahydraulic pump, means operatively coupling said pump to said enginemeans, at least two hydraulic motors, means operatively connecting saidpump to said motors and means operatively connecting each of said motorsto one of said generators.

11. A machine as claimed in claim l, further comprising means foroperating said generator in front of said rollers to produce a firstoscillation frequency and means for driving tion frequency differentfrom said first oscillation frequency.

l2. A machine as claimed in claim l. comprising at least two pairs ofsaid generators, and means detachabl y mounting each of said pairs ofgenerators on said frame.

1. In a soil compacting machine including a frame, at least two soilcompacting rollers, means mounting said rollers in tandem in said frame,at least two out of balance centrifugal force generators and meansmounting said generators in said frame, the improvement wherein saidgenerator mounting means includes first means mounting at least one ofsaid generators in front of said rollers and second means mounting atleast one other of said generators behind said rollers both said firstmeans and said second means including a relatively short shaft extendingin the direction of travel of said machine.
 2. A machine as claimed inclaim 1, wherein said means mounting said rollers in said frame includeshorizontal axle means and further comprising bearing means mounting saidshafts of said first and said second means at substantially the sameheight as said axle means.
 3. A machine as claimed in claim 1, whereinsaid frame includes longitudinal side members and transverse membersinterconnecting said longitudinal side members in front of and behindsaid rollers, said transverse members including portions defininghousings and said generator mounting means mounting said generators insaid housings.
 4. A machine as claimed in claim 1, wherein said frameincludes longitudinal side members disposed one at each end of saidrollers and further comprising engine means and drive means operativelyconnecting said generators to said engine, said drive means beinglocated above said rollers and between vertical planes containing saidlongitudinal side members.
 5. A machine as claimed in claim 1, whereineach of said generators includes a pair of unbalanced discs, meansrotatably mounting said discs and means for rotating said discs inopposite directions to each other.
 6. A machine as claimed in claim 5,further comprising peripheral teeth on said discs, said teeth of saiddiscs in each of said pairs of discs meshing with each other.
 7. Amachine as claimed in claim 5, further comprising peripheral teeth onsaid discs and toothed belt means meshing with said teeth on said discsof each of said pairs.
 8. A machine as claimed in claim 7, furthercomprising teeth on both sides of said belt, an idler roller, and meansextending said belt around said idler roller, around one of said discsin said pair in a clockwise direction and around the other of said discsin said pair in an anticlockwise direction.
 9. A machine as claimed inclaim 1, further comprising means for driving said generators, meansmounting said driving means on said frame and universally jointed shaftmeans operatively connecting said driving means to said generators. 10.A machine as claimed in claim 1, including engine means for driving saidgenerators, means mounting said engine means on said frame, a hydraulicpump, means operatively coupling said pump to said engine means, atleast two hydraulic motors, means operatively connecting said pump tosaid motors and means operatively connecting each of said motors to oneof said generators.
 11. A machine as claimed in claim 1, furthercomprising means for operating said generator in front of said rollersto produce a first oscillation frequency and means for driving saidgenerator behind said rollers to produce a second oscillation frequencydifferent from said first oscillation frequency.
 12. A machine asclaimed in claim 1, comprising at least two pairs of said generators,and means detachably mounting each of said pairs of generators on saidframe.